KR102217908B1 - Exhaust Gas Reduction Apparatus for Diesel Engine using exhaust gas after DPF as air source for burner - Google Patents

Abstract

The present invention is a smoke reduction device that uses the exhaust gas that has passed through the DPF as an oxygen supply source. Unlike the forced regeneration method of DPF by directly heating the exhaust gas discharged from the conventional engine, the DPF is heated by heating the exhaust gas that has passed through the DPF. It suggests a method to use for forced regeneration.

Description

Exhaust Gas Reduction Apparatus for Diesel Engine using exhaust gas after DPF as air source for burner}

The present invention relates to a smoke reduction device having a DPF, and more specifically, a technology related to a smoke reduction device using exhaust gas that has passed through the DPF as an oxygen supply source of the burner.

Diesel post-treatment devices include a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), a SeIective Catalytic Reduction (SCR), and a Lean NOx Trap (LNT). Among them, DPF is a filter that filters soot particles, and when more than a certain amount of soot is collected in the filter, it is a system that oxidizes the collected soot to regenerate the filter. As a regeneration method for stable use of such a DPF system, it can be classified into a passive DPF method and a forced regeneration (active DPF, or complex regeneration) method.

In the natural regeneration method, the temperature of the exhaust gas is increased by an oxidation catalyst added in the soot filter, and the soot is continuously oxidized by using oxygen and nitrogen dioxide in the exhaust gas. However, this natural regeneration method has a problem in that it is difficult to expect a smooth regeneration effect of the soot filtration filter when the temperature of the exhaust gas does not significantly reach the catalyst activation temperature required for natural regeneration.

On the contrary, in the forced regeneration or combined regeneration method, when a certain amount of soot is collected in the filter, the exhaust gas temperature is raised to the oxidizable temperature of soot by using a forced heating means, and the soot filtration filter is regenerated at appropriate times. It is a means to continuously maintain the performance of the DPF system and the engine.

In order to forcibly regenerate the filter of the DPF system, a flame must be generated in the burner. At this time, oxygen is required to generate the flame. Referring to the prior art of FIG. 1, the exhaust gas inlet 1'and the exhaust gas outlet 2 '), (fuel injection) nozzle (4'), spark plug (3'), in the exhaust gas reduction device including the DPF (6'), external air is supplied through the compressor (5') as a source of oxygen supplied to the burner. Although injected, this method has the disadvantage of having to separately install a compressor 5'.

In order to solve the above problem, the exhaust gas branch pipe branched from the inlet 1 ′ is branched from the inlet 1 ′ so that some of the exhaust gas is used as an oxygen supply source for generating a flame by branching the inlet 1 ′ of the exhaust gas as shown in FIG. 7'), a technology that uses a part of the exhaust gas as an oxygen supply source for the burner has been proposed. That is, since about 10% of oxygen is also contained in the exhaust gas discharged after combustion from the engine, this technology uses the oxygen in the exhaust gas as an oxygen supply source of the burner unit.

However, in the system as shown in FIG. 2, there is a problem that a lot of pollutants accumulate in the exhaust gas reduction device by using the exhaust gas as an oxygen supply source. 3A is a photograph of contaminants formed in a burner portion when a part of conventional exhaust gas is used as an oxygen supply source for the burner portion. When a part of the exhaust gas is used as an oxygen supply source of the burner unit as shown in FIG. 2, there is a problem in that contaminants such as soot are deposited on the burner unit and the inner wall of the combustion chamber due to pollutants such as PM contained in the exhaust gas. Due to these pollutants, eventually, when the DPF is forcibly regenerated, regeneration cannot be uniformly performed for each area of the filter. 3B is a picture after regeneration of the DPF in the DPF system using the conventional exhaust gas as the oxygen supply source of the burner, which is divided into black and white, which means that filter regeneration was not uniformly performed. One of the causes of this filter regeneration unevenness is that soot and the like as shown in FIG. 3A are accumulated in the DPF.

Patent Registration No. 10-1587217 Patent Registration No. 10-0925871

The present invention is a novel technology capable of solving the problem of pollution inside the exhaust gas reduction device due to exhaust gas used as the oxygen supply source of the burner unit in the exhaust gas as an oxygen supply source of the burner unit for forced regeneration of DPF It aims to provide.

The present invention is provided with a space therein, a housing including an inlet through which exhaust gas burned in the engine is introduced and an outlet through which exhaust gas passing through the DPF is discharged to the outside; A combustion chamber installed inside the housing and spaced apart from the inner wall of the housing by a predetermined distance; A burner unit internally communicated with the combustion chamber and positioned in front of the combustion chamber, the burner unit including a spark plug for generating a spark and a nozzle located at a distance adjacent to the spark plug for injecting fuel supplied to generate a flame; A DPF installed in the housing and located behind the combustion chamber; And an exhaust gas recirculation line for recirculating some of the exhaust gas passing through the DPF and transferring it to the burner unit. The exhaust gas passing through the DPF is used as an oxygen supply source for the burner unit.

Particularly, a blocking part is provided from the outer boundary of the burner part and the combustion chamber to the inner wall of the housing, and a first space part is located between the combustion chamber and the inner wall of the housing, and a second space part may be located between the burner part and the inner wall of the housing.

Particularly, the exhaust gas introduced from the inlet may be introduced into the first space, and the exhaust gas recirculated through the exhaust gas recirculation line may be introduced into the second space.

In particular, it is preferable that a plurality of through holes are installed outside the burner part, and exhaust gas injected into the second space part through the exhaust gas recirculation line is injected into the burner part through the through hole.

In particular, a plurality of through-holes are installed in the outer periphery of the combustion chamber, so that a part of the exhaust gas flowing into the first space through the inlet may be introduced into the combustion chamber.

In particular, there is at least one combustion chamber diaphragm extending from the outside of the combustion chamber to the inner wall of the housing, and the combustion chamber diaphragm has at least one through hole so that the exhaust gas flowing into the first space portion is directed toward the DPF through the through hole of the combustion chamber diaphragm Can be moved to.

In particular, the exhaust gas recirculation line may be directly connected to the inside of the burner unit.

The exhaust gas that passes through the DPF of the present invention is used as an oxygen supply source for the burner. Unlike the exhaust gas emission from the conventional engine, the exhaust gas is directly used as an oxygen supply source for the burner. By using clean exhaust gas as an oxygen supply source of the burner unit, foreign substances such as soot do not accumulate inside the soot reduction device, so not only the overall efficiency of the exhaust reduction device is improved, but also the DPF can be smoothly regenerated.

1 is an example of using air in the atmosphere by using a compressor as an oxygen supply source of a burner unit as a conventional exhaust emission reduction device including a DPF.
2 is an example of a conventional exhaust gas reduction device including a DPF, in which exhaust gas generated from an engine is directly used as an oxygen supply source of a burner unit.
3A is a photograph of contaminants formed in the burner unit when a part of the exhaust gas generated from the conventional engine is used as an oxygen supply source for the burner unit, and Fig. 3B is a view of the DPF after forced regeneration of the DPF of the exhaust gas reduction device of Fig. 3A. It's a picture.
4 is a schematic cross-sectional view of an exhaust gas reducing apparatus using exhaust gas passing through a DPF as an oxygen supply source of a burner unit as a first preferred embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of an exhaust gas reducing apparatus using exhaust gas passing through a DPF as an oxygen supply source of a burner unit as a second preferred embodiment of the present invention.
FIG. 6 is a cross-sectional view of an exhaust gas reducing apparatus using an exhaust gas passing through a DPF having a DOC as an oxygen supply source of a burner unit as a third preferred embodiment of the present invention.

The present invention is a technology related to a soot reduction device having a DPF, the soot reduction device of the present invention essentially includes a DPF, and may further include a DOC in front of the DPF. The present invention uses exhaust gas when generating flames for forced regeneration of DPF, but conventionally, exhaust gas generated from the engine was directly used as an oxygen supply source, but in the present invention, relatively clean exhaust gas from which PM is removed through DPF. By using as the oxygen supply source of the burner, it is possible to reduce the generation of pollutants such as soot in the smoke reduction device.

Hereinafter, the present invention will be described with reference to the drawings.

4 is a schematic cross-sectional view of an exhaust gas reducing apparatus using exhaust gas passing through a DPF as an oxygen supply source of a burner unit as a first preferred embodiment of the present invention.

The exhaust gas reduction device 100 of the present invention is based on the housing 10 serving as an external body, except for the exhaust gas recirculation line 50, the remaining components such as the burner unit 40, the combustion chamber 30, and the DPF. The 20 is preferably located inside the housing 10, but is not limited thereto. Hereinafter, each configuration will be described.

The housing 10 is a structure that serves as the body of the exhaust emission reduction device 100, and is generally cylindrical, and in the front of the cylindrical shape (the left side is referred to as the front and the right side is referred to as the rear based on the drawings in the description below), a burner unit to be described later ( 40) is located, and an exhaust port 12 through which exhaust gas passing through the DPF is discharged is located at the rear. The housing 10 generally has a cylindrical shape with a cone shape at both ends and a narrow diameter. In particular, the burner portion 40 is located in the cone-shaped portion in front. In general, the inlet 11 through which the exhaust gas burned from the engine is introduced is located vertically with respect to the side of the housing 10, but the inlet 11 may be installed on the side of the housing 10 in a diagonal direction.

The interior of the housing 10 is an overall hollow structure, and a combustion chamber 30 installed at a certain distance from the inner wall of the housing 10 is located. The combustion chamber 30 serves to heat the exhaust gas flowing into the inlet 11 as the flame generated from the burner unit 40 spreads out. A cylindrical case forming the combustion chamber 30 may have a plurality of through holes 31 through which exhaust gas can be introduced. In this case, exhaust gas may penetrate into some of the combustion chambers 30 through the through holes 31. Even if there is a through hole 31, most of the inflowing exhaust gas moves to the DPF 20 through the combustion chamber diaphragm 14 to be described later.

The combustion chamber diaphragm 14 increases the residence time of the exhaust gas in order to prevent the exhaust gas from exiting the combustion chamber 30 excessively quickly, so that the temperature does not rise sufficiently in the combustion chamber 30 and exits the DPF 20. Not only does it play a role, but it also plays a role in ensuring uniform mixing before exiting the exhaust gas combustion chamber. The combustion chamber diaphragm 14 is configured in a circular band shape on the outer periphery of the combustion chamber 30, and a plurality of through holes 14a are formed to allow exhaust gas to escape in the direction of the DPF 20 through the through holes 14a. Can be. Further, in order to increase the residence time of the exhaust gas in the combustion chamber, the combustion chamber diaphragm 14 may be configured in multiple stages.

On the other hand, the burner unit 40 has a structure that is in communication with the combustion chamber 30, and the burner unit 40 is also generally cylindrical in shape. The burner unit 40 is provided with a spark plug 42 and a nozzle 41 for injecting fuel. Fuel, which is a raw material of the flame, is supplied through the nozzle 41, and the fuel is ignited by the flame of the spark plug 42. The burner unit 40 is configured to be in communication with the rear combustion chamber 30, so that the flame generated in the burner unit 40 moves to the combustion chamber 30. When a flame is formed in the front space of the combustion chamber 30 due to the burner unit 30, oxygen must be supplied to the burner unit 40 in order to maintain a stable flame.

In addition, the burner unit 40 and the combustion chamber 30 have a single cylindrical structure, and the vicinity where the nozzle 41 and the spark plug 42 are located is referred to as the burner unit 40, and the rear end thereof is the combustion chamber 30. Only divided into, it may have a structure in which the burner unit 40 and the combustion chamber 30 cannot be physically accurately separated.

An exhaust gas blocking film 13 is installed at the boundary between the burner unit 40 and the combustion chamber 30 so that the exhaust gas flowing into the housing 10 through the inlet 11 cannot enter the burner unit 40. The blocking film 13 is formed in a donut shape in a vertical circle from the outer wall of the combustion chamber 30 and the burner unit 40 to the inner wall of the housing 10, so that the exhaust gas entering the inlet 11 is transferred to the blocking film 13 As a result, it passes through the combustion chamber 30 and proceeds in the direction of the DPF 20. As shown in FIG. 4, a space on the side of the combustion chamber 30 among the spaces divided by the blocking film 13 is referred to as a first space portion 15, and a space on the side of the burner portion 40 is referred to as a second space portion 16. In addition, the space in which the exhaust gas behind the DPF 20 is discharged will be referred to as a third space part 17.

It may have one or more through holes 31 formed along the outer periphery of the combustion chamber 30, and in this case, some of the exhaust gas introduced through the inlet 11 may enter the combustion chamber 30 through the through holes 31 In addition, a part of the flame may also come out of the first space 15 outside the combustion chamber 30 through the through hole 31.

As shown in FIG. 4, in the present invention, unlike the prior art FIGS. 1 and 2, oxygen is separately supplied from the outside through a compressor, or the exhaust gas entering through the inlet 11 is directly used as an oxygen supply source of the burner unit 40 Rather, in order to use relatively clean exhaust gas from which PM has been removed through the DPF 20 as an oxygen supply source of the burner unit 40, the exhaust gas discharged from the rear of the DPF 20, that is, the third space unit An exhaust gas recirculation line 50 for supplying the exhaust gas of 17 to the burner unit 40 is provided.

The exhaust gas recirculation line 50 is connected so as to be in inner communication with the second space 16 in the first preferred embodiment of FIG. 4, and the exhaust gas entering the second space 16 is passed through the through hole of the burner 40. 43) through the burner part 40 to enter the interior. The exhaust gas recirculation line 50 may be further provided with a valve for turning on and off the movement of the exhaust gas, but is not shown in the drawing. In addition, if necessary, the exhaust gas recirculation line 50 may be provided in plural number for smooth movement of the exhaust gas.

On the other hand, Figure 5 is a second preferred embodiment 200 of the present invention, the connection point between the burner unit 40 and the exhaust gas recirculation line 50 is different from the first preferred embodiment 100 of Figure 4, and exhaust The gas recirculation line 50 may be configured to be directly connected to the inside of the burner unit 40 instead of the second space unit 16. That is, in the first embodiment (100), the exhaust gas that has passed through the DPF (20) flows into the second space (16) and then enters the internal space of the burner (40) through the through hole (43). , In the second embodiment 200, the exhaust gas passing through the DPF 20 may be directly introduced into the internal space of the burner unit 40.

6 is an example of a DPF exhaust emission reduction device 300 according to a third preferred embodiment of the present invention, in which a DOC 60 is further provided at the front end of the DPF 20. Referring to FIG. 6, a DOC 60 is further provided at the front end of the DPF 20 to first remove hydrocarbons or carbon monoxide, and then particulates may be collected in the DPF 20.

10: housing 11: inlet
12: outlet 13: blocking film
14: combustion chamber diaphragm 15: first space portion
16: second space part 17: third space part
20: DPF 30: combustion chamber
31: through hole 40: burner part
41: nozzle 42: spark plug
43: through hole 50: exhaust gas recirculation line
60: DOC

Claims (7)

A housing provided with a space therein and including an inlet through which exhaust gas burned from the engine is introduced and an outlet through which exhaust gas passing through the DPF is discharged to the outside;
A combustion chamber installed inside the housing and spaced apart from the inner wall of the housing by a predetermined distance;
A burner unit internally communicated with the combustion chamber and positioned in front of the combustion chamber, the burner unit including a spark plug for generating a flame and a nozzle for injecting fuel to generate a flame;
A DPF installed in the housing and located behind the combustion chamber; And
As an exhaust gas reduction device comprising an exhaust gas recirculation line for recirculating part of the exhaust gas passing through the DPF and transferring it to the burner unit,
A blocking film is provided from the boundary between the burner unit and the combustion chamber to the inner wall of the housing, and a first space is positioned between the combustion chamber and the inner wall of the housing, and a second space is positioned between the burner unit and the inner wall of the housing,
Exhaust gas introduced from the inlet is introduced into the first space, and exhaust gas recirculated to the burner through the exhaust gas recirculation line is introduced into the second space,
Exhaust through the DPF, characterized in that a plurality of through holes are installed outside the burner part, and exhaust gas injected into the second space part through the exhaust gas recirculation line is injected into the burner part through the through hole. An exhaust reduction device that uses gas as an oxygen supply source for the burner.
A housing provided with a space therein and including an inlet through which exhaust gas burned from the engine is introduced and an outlet through which exhaust gas passing through the DPF is discharged to the outside;
A combustion chamber installed inside the housing and spaced apart from the inner wall of the housing by a predetermined distance;
A burner unit internally communicated with the combustion chamber and positioned in front of the combustion chamber, the burner unit including a spark plug for generating a flame and a nozzle for injecting fuel to generate a flame;
A DPF installed in the housing and located behind the combustion chamber; And
As an exhaust gas reduction device comprising an exhaust gas recirculation line for recirculating part of the exhaust gas passing through the DPF and transferring it to the burner unit,
A blocking film is provided from the boundary between the burner unit and the combustion chamber to the inner wall of the housing, and a first space is positioned between the combustion chamber and the inner wall of the housing, and a second space is positioned between the burner unit and the inner wall of the housing,
There is at least one combustion chamber diaphragm extending from the outside of the combustion chamber to the inner wall of the housing, and the combustion chamber diaphragm has at least one through hole so that the exhaust gas flowing into the first space part moves in the direction of DPF through the through hole of the combustion chamber diaphragm. An exhaust gas reduction device using the exhaust gas that has passed through the DPF as an oxygen supply source for the burner.
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